Fog producing spray nozzle



3811- 1950 H. w. CAUSER oe PRODUCING SPRAY NOZZLE Filed May 17, 1945 atented Jan. 24, 1950 UNITED STATES PATENT OFFICE FOG PRODUCING SPRAY NOZZLE Herbert W. Causcr, Wcymouth, Mass assignor to Factory Mutual Research Corporation, Boston, Mass a corporation of Massachusetts Application May 17, 1945; Serial No. 594,313

v 3 Claims.

This invention relates to a device for producing a fog of water particles or other material for use in extinguishing fires or as a screen or for other purposes, in contradistinction to an ordinary sprinkler nozzle which merely distributes water in relatively large globules over a wide area. The invention is particularly useful in extinguishing fires in vats or tanks of kerosene, fuel oil, rubber cement, lacquer and other inflammable liquids, which are difficult to extinguish but which can be smothered by replacing the surrounding air with a fog of material incapable of supporting combustion. For example the devices of the present invention may be used to advantage in lieu of the spray nozzles disclosed in Patent 2,283,775 of Norman J. Thompson. This invention constitutes an improvement on the subjectmatter of my copendlng patent Serial No. 507,068 filed October 21, 1943.

One difliculty with prior nozzles is that they produce a spray having a relatively hollow center so that the effect of the spray is uneven throughout its cross-sectional area, being relatively ineifectual along the axis. Another diifl eulty is that they tend to draw in the surrounding air, thereby facilitating combustion and making it more diflicult to extinguish the 1116.

Objects of the invention are to produce a device of the character referred to which is simple and economical to manufacture, which is reliable and emcient in use, which does not require excessively high pressure, which does not clog easily, which aifords practically uniform distribution of fog throughout the cross-sectional area of the delivered stream, which delivers exceptionally fine fog, which has less tendency to draw in the surrounding air, and which is generally superior to the devices of the prior art.

According to the present invention the device comprises inner and outer flaring coaxial bailies with a space therebetween having an inlet for water or other fluid and means for directing a sheet of the water along the outer surface of the outer baille from the smaller end toward the larger end, the outer baifle having outlets distributed around its circumference through which streams may flow outwardly from the aforesaid space to break up the aforesaid sheet and produce fog. Preferably the aforesaid inlet is adjacent the smaller ends of the baflles and the outlets are adjacent the larger end of the outer baifle. In the preferred embodiment there are a plurality of inlets and they enter the aforesaid space through the smaller end of the outer bailie. The space between the two bailies is preferably closed except for the aforesaid inlets and outlets. Themes of the inlets should be approximately parallel with the axes of the baflles. that is the longitudinal elements of the walls of the inlets should be approximately parallel with the axes oi the baifles irrespective of the cross-sectional outlines of the inlets. Preferably the outlets comprise slots which extend to the larger end of the outer baille to form fingers therebetween, and the ends of the fingers extend into juxtaposition to the larger end of the inner battle. The flare of the inner baflle preferably increases at its larger end to deflect the water outwardly through the outlets. While the two bailles may be cast or otherwise formed as a single part they are preferably formed in two parts and then secured together either permanently or detachably.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawing in which Fig. 1 is a side elevation with a part broken away;

Fig. 2 is a side elevation, taken at right-angles to that shown in Fig. 1, with a portion in section;

Fig. 3 is an end view; and

Fig. 4 is a section on line 4-4 of Fig. 3.

The particular embodiment chosen for the pur-. pose of illustration comprises a nozzle 1 having a reduced outlet 2 and a threaded end 3 adapted to be screwed into a pipe coupling, in combination with the aforesaid baflles in the form of hollow truncated cones 4 and 5. The cones are joined to the nozzle by means of two arms 8 which meet in a tapered head I which constitutes the apex of the baflle. The opening in the small end of the outer baflie is large enough to receive the end of the inner baille, and the inner ballle is provided with a shoulder seating on the outer baiile around its axial opening. The two bailles may be secured together and to the head I in any suitable way;- in the drawing they are secured by being welded together and to the apex, the welding material being indicated at 8. By thus assembling the parts, a single ring of welding material secures the two baflles together and to the apex I. In the illustration the nozzle is closed by a cap [2 which is held in place by two struts l3 and a fusable link ll, one strut seating on the cap 12 and the other strut seating on an adjusting screw I l which may be threaded back and forth independently oi! the baiiles 4 and 5.

As shown in Fig. 4 the baflles I and 5 are shaped to leave a space therebetween. The outer bailie is provided with circular opening l6 near its smaller end to form inlets and with slots l1 extending from the larger end toward the smaller end to form outlets. The slots and openings should have sharp edges to permit the water to enter and leave the space with less turbulence and therefore in greater quantity and with greater velocity. As shown in Figs. 3 and 4 the axes of the openings l6 are parallel with the axes of the bailies. While the dimensions of the various parts may be varied to suit different conditions of use, for most purposes they are preferably substantially as shown in Figs. 1 and 2. In installations where these devices are mounted over a tank or vat they are preferably distributed around the periphery of the tank or vat as disclosed in the aforesaid patent, about three feet apart and about eight feet above the level of the liquid in the tank or vat.

In operation the jet of water issuing from the orifice 2 is divided by the apex 1 into a conical sheet which flows along the outer surface of the outer bailie. Some of this water flows into the space between the baiiles through the inlets l6 and thence outwardly through the outlets l1. As shown in Fig. 4 the flare of the inner baflle increases near its larger end to form a bell-shaped lip which extends outwardly substantially to the tips of the fingers between the slots l'l, thereby deflecting the water which enters through opening l6 and causing it to emerge through slots ll in a direction crosswise of the sheet of water flowing lengthwise of the outer surface of the outer baiiie. In thus cutting across the sheet of water the jets issuing through slots I! break up the water into very fine particles. Not only does this arrangement produce a fine fog which is exceptionally effective in extinguishing difficult fires, but for some reason not clearly understood the portion of the fog stream in line with the axis of the device contains approximately as much fog per unit volume as the surrounding portions in line with the outer surface of the outer baifle. Moreover the device has less tendency to draw in surrounding air. Consequently these devices are exceptionally eflicient in extinguishing fires in tanks of naphtha and other diificult fires.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of r for admitting water into said space, whereby water flowing into the space is directed outwardly by said flaring surface through said openings in the first baflle to form jets which intersect said sheet at the outer surface of the first baflle, thereby to break up the sheet into fog.

2. For producing fog, a device comprising a first conical baflie having inlets distributed around its smaller end and openings through the baiile distributed around its circumference at its larger end, a second conical baille disposed within said first conical battle with a space between the two bailles, the larger end of the second baflle having a flaring surface directed toward said openings and at an angle to the outer surface of the first bailie, and means for directing a sheet of water along the outer surface of said first baflie from its smaller end toward its larger end, whereby water from said sheet may enter said space through said inlets and thence be directed outwardly by said flaring surface through said openings to form jets which intersect said sheet at the outer surface of the first baflle thereby to break up the sheet into fog.

3. For producing fog, a device comprising a first conical baifle having inlets distributed around its smaller end and slots through the baflie distributed around its circumference and extending longitudinally from its larger end to form fingers between the slots, a second conical baflle disposed within said first battle with a space between the two baflles, the larger end of said second baflle having a flaring surface directed toward said slots and at an angle to the outer surface of the first baflle, and means for directing a sheet of water along the outer surface of said baflle from its smaller end toward its larger end, whereby water from said sheet may enter said space through said inlets and thence be directed outwardly by said flaring surface through said slots to form jets which intersect said sheet at the outer surface of the first baffle, thereby to break up the sheet into fog.

HERBERT W. CAUSER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,674,480 Nelson June 19, 1928 1,837,3 2 Hamilton Dec. 22, 1931 2,076,483 Rowley Apr. 6, 1937 2,391,616 Causer Dec. 25, 1945 FOREIGN PATENTS Number Country Date 160,428 Germany May 8, 1905 471,050 Germany Feb. 5, 1929 

